I. Field
The present disclosure relates generally to communication, and more specifically to techniques for transmitting data in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
A wireless communication system may employ hybrid automatic repeat request (HARQ) to improve reliability of data transmission. With HARQ, a transmitter may generate multiple subpackets for a data packet and may send one or more subpackets until the packet is decoded correctly by a receiver or the maximum number of subpackets has been sent. Different packets may be successfully decoded with different numbers of subpackets depending on channel conditions and other factors.
The transmitter may send data to the receiver via one or more links. Each link may be associated with certain radio resources (e.g., a different carrier) usable for data transmission. If there is only one link, then the transmitter may send packets sequentially via this link, one packet at a time. The receiver would then receive the packets in the proper order. If there are multiple links, then the transmitter may send multiple packets in parallel via these links. These multiple packets may terminate at different times depending on the number of subpackets needed for each packet. It may be desirable to send the packets in a manner such that the packets can be received either in order or with as few packets out of order as possible.